He found it on the floor. Started looking excited and sniffing it so I shooed him away from it but then needed to get something to pick the slug up in and when I got back he was onto the slug again and having a go at it by the look of it, and when I tried to move him he quickly pouched the whole thing! I then spent over an hour with him on my knee trying to get him to depouch it and it failed and he sat there stubbornly. It was early hours by then so I gave up and put him back in the cage. Next day I checked his hoard and his cage. No slug to be seen! I had expected to find gungy remnants but not a thing! Phoned the vet as was worried about bloodworms and was reassured that these wouldn't likely survive in a hamster digestive system as it was not a familiar environment for them. So I assume he had eaten the whole thing - never found any remnants. And he stayed perfectly well until a good old age.